Thermal error caused by the thermal deformation is one of the most significant factors influencing the accuracy of the machine tool. Among all the heat sources which lead to the thermal distortions, ...the spindle is the main one. This paper presents an overview of the research about the compensation of the spindle thermal error. Thermal error compensation is considered as a more convenient, effective and cost-efficient way to reduce the thermal error compared with other thermal error control and reduction methods. Based on the analytical calculation, numerical analysis and experimental tests of the spindle thermal error, the thermal error models are established and then applied for implementing the thermal error compensation. Different kinds of methods adopted in testing, modeling and compensating are listed and discussed. In addition, because the thermal key points are vital to the temperature testing, thermal error modeling, and even influence the effectiveness of compensation, various approaches of selecting thermal key points are introduced as well. This paper aims to give a basic introduction of the whole process of the spindle thermal error compensation and presents a summary of methods applied on different topics of it.
•Thermal error compensation is an effective and economical way to reduce the error.•Analyzing, testing, modeling and compensating are main aspects of the research.•Various devices and systems for temperature and thermal error testing are introduced.•Different kinds of methods used for thermal error modeling are studied.•Two commonly used mechanisms of thermal error compensation are explained.
Aberrant RNA splicing is recognized to contribute to cancer pathogenesis, but the underlying mechanisms remain mainly obscure. Here, we report that the splicing factor SRSF2 is upregulated frequently ...in human hepatocellular carcinoma (HCC), where this event is associated with poor prognosis in patients. RNA-seq and other molecular analyses were used to identify SRSF2-regulated alternative splicing events. SRSF2 binding within an alternative exon was associated with its inclusion in the RNA, whereas SRSF2 binding in a flanking constitutive exon was associated with exclusion of the alternative exon. Notably, cancer-associated splice variants upregulated by SRSF2 in clinical specimens of HCC were found to be crucial for pathogenesis and progression in hepatoma cells, where SRSF2 expression increased cell proliferation and tumorigenic potential by controlling expression of these variants. Our findings identify SRSF2 as a key regulator of RNA splicing dysregulation in cancer, with possible clinical implications as a candidate prognostic factor in patients with HCC.
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Epigenetic variation has been proposed to facilitate adaptation to changing environments, but evidence that natural epialleles contribute to adaptive evolution has been lacking. Here we identify a ...retrotransposon, named "NMR19" (naturally occurring DNA methylation variation region 19), whose methylation and genomic location vary among Arabidopsis thaliana accessions. We classify NMR19 as NMR19-4 and NMR19-16 based on its location, and uncover NMR19-4 as an epiallele that controls leaf senescence by regulating the expression of PHEOPHYTIN PHEOPHORBIDE HYDROLASE (PPH). We find that the DNA methylation status of NMR19-4 is stably inherited and independent of genetic variation. In addition, further analysis indicates that DNA methylation of NMR19-4 correlates with local climates, implying that NMR19-4 is an environmentally associated epiallele. In summary, we discover a novel epiallele, and provide mechanistic insights into its origin and potential function in local climate adaptation.
Puccinellia tenuiflora is the most saline-alkali tolerant plant in the Songnen Plain, one of the three largest soda saline-alkali lands worldwide. Here, we investigated the physicochemical properties ...of saline-alkali soils from the Songnen Plain and sequenced the transcriptomes of germinated P. tenuiflora seedlings under long-term treatment (from seed soaking) with saline-alkali soil extracts.
We found that the soils from Songnen Plain were reasonably rich in salts and alkali; moreover, the soils were severely deficient in nitrogen N, phosphorus P, potassium K and several other mineral elements. This finding demonstrated that P. tenuiflora can survive from not only high saline-alkali stress but also a lack of essential mineral elements. To explore the saline-alkali tolerance mechanism, transcriptional analyses of P. tenuiflora plants treated with water extracts from the saline-alkali soils was performed. Interestingly, unigenes involved in the uptake of N, P, K and the micronutrients were found to be significantly upregulated, which indicated the existence of an efficient nutrition-uptake system in P. tenuiflora. Compared with P. tenuiflora, the rice Oryza sativa was hypersensitive to saline-alkali stress. The results obtained using a noninvasive microtest techniques confirmed that the uptake of NO
and NH
and the regulatory flux of Na
and H
were significantly higher in the roots of P. tenuiflora than in those of O. sativa. In the corresponding physiological experiments, the application of additional nutrition elements significantly eliminated the sensitive symptoms of rice to saline-alkali soil extracts.
Our results imply that the survival of P. tenuiflora in saline-alkali soils is due to a combination of at least two regulatory mechanisms and the high nutrient uptake capacity of P. tenuiflora plays a pivotal role in its adaptation to those stress. Taken together, our results highlight the role of nutrition uptake in saline-alkali stress tolerance in plants.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Thermal error caused by thermal deformation is one of the most significant factors influencing the accuracy of the machine tool. Compensation is a practical and efficient method to reduce the thermal ...error. Among all the thermal error compensation processes, thermal error modeling is the premise and basis because the effectiveness of the compensation is directly determined by the accuracy and robustness of modeling. In this paper, an overview of the thermal error modeling methods that have been researched and applied in the past ten years is presented. First, the modeling principle and compensation methods of machine tools are introduced. Then, the methods are classified and summarized in detail. Finally, the future research trend of thermal error modeling is forecasted.
Lindera aggregata , a member belongs to the genus Lindera of Lauraceae family. Its roots and leaves have been used as traditional Chinese medicine or functional food for thousands of years. However, ...its mitochondrial genome has not been explored. Our aim is to sequence and assemble the mitogenome of L. aggregata to elucidate the genetic mechanism and evolutionary pathway. The results had shown that the mitogenome was extremely complex and had a unique multi-branched conformation with total size of 912,473 bp. Comprehensive analysis of protein coding genes of 7 related species showed that there were 40 common genes in their mitogenome. Interestingly, positive selection had become an important factor in the evolution of ccmB , ccmFC , rps10 , rps11 and rps7 genes. Furthermore, our data highlighted the repeated trend of homologous fragment migrations between chloroplast and mitochondrial organelles, and 38 homologous fragments were identified. Phylogenetic analysis identified a tree that was basically consistent with the phylogeny of Laurales species described in the APG IV system. To sum up, this study will be helpful to the study of population genetics and evolution of Lindera species.
Serine/arginine-rich (SR) proteins are important splicing factors in plant development and abiotic/hormone-related stresses. However, evidence that SR proteins contribute to the process in woody ...plants has been lacking. Using phylogenetics, gene synteny, transgenic experiments, and RNA-seq analysis, we identified 24
genes and explored their evolution, expression, and function in
. The
genes were divided into six subfamilies, generated by at least two events of genome triplication and duplication. Notably, they were constitutively expressed in roots, stems, and leaves, demonstrating their fundamental role in
. Additionally, most
genes (~83%) responded to at least one stress (cold, drought, salt, SA, MeJA, or ABA), and, especially, cold stress induced a dramatic perturbation in the expression and/or alternative splicing (AS) of 18
genes (~75%). Evidentially, the overexpression of
in
decreased freezing tolerance, which probably resulted from AS changes of the genes (e.g.,
and
) critical for cold tolerance. Moreover, the transgenic plants were salt-hypersensitive at the germination stage. These indicate that
may act as a negative regulator under cold and salt stress. Altogether, this study sheds light on the evolution, expression, and AS of
genes, and the functional mechanisms of
in woody plants.
The phytohormone abscisic acid (ABA) is important for growth, development and stress responses in plants. Recent research has identified ABA receptors and signalling components that regulate seed ...germination and stomatal closure. However, proteins that regulate ABA signalling remain poorly understood. Here we use a forward-genetic screen to identify rbm25-1 and rbm25-2, two Arabidopsis mutants with increased sensitivity to growth inhibition by ABA. Using RNA-seq, we found that RBM25 controls the splicing of many pre-mRNAs. The protein phosphatase 2C HAB1, a critical component in ABA signalling, shows a dramatic defect in pre-mRNA splicing in rbm25 mutants. Ectopic expression of a HAB1 complementary DNA derived from wild-type mRNAs partially suppresses the rbm25-2 mutant phenotype. We suggest that RNA splicing is of particular importance for plant response to ABA and that the splicing factor RBM25 has a critical role in this response.
Plants respond to cold stress by inducing the expression of transcription factors that regulate downstream genes to confer tolerance to freezing. We screened an Arabidopsis transfer DNA (T-DNA) ...insertion library and identified a cold-hypersensitive mutant, which we named stch4 (sensitive to chilling 4). STCH4/REIL2 encodes a ribosomal biogenesis factor that is upregulated upon cold stress. Overexpression of STCH4 confers chilling and freezing tolerance in Arabidopsis. The stch4 mutation reduces CBF protein levels and thus delayed the induction of C-repeat-binding factor (CBF) regulon genes. Ribosomal RNA processing is reduced in stch4 mutants, especially under cold stress. STCH4 associates with multiple ribosomal proteins, and these interactions are modulated by cold stress. These results suggest that the ribosome is a regulatory node for cold stress responses and that STCH4 promotes an altered ribosomal composition and functions in low temperatures to facilitate the translation of proteins important for plant growth and survival under cold stress.
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•STCH4 maintains rRNA processing under low temperatures•STCH4 promotes CBF translation under low temperatures•Overexpression of STCH4 enhances cold stress tolerance•STCH4 may be required for ribosome remodeling under low temperatures
Yu et al. show that the ribosomal biogenesis factor STCH4 confers cold stress tolerance in Arabidopsis by maintaining rRNA processing and promoting CBF protein translation. The ribosome is likely a site for cold stress response.
Dysregulated alternative splicing events have been implicated in many types of cancer, but the underlying molecular mechanisms remain unclear. Here, we observe that the splicing factor SRSF1 ...regulates DBF4B exon6 splicing by specifically binding and promoting its inclusion. Knockdown of the exon6-containing isoform (DBF4B-FL) significantly inhibits the tumorigenic potential of colon cancer cells in vitro and in mice, and SRSF1 inactivation phenocopies DBF4B-FL depletion. DBF4B-FL and SRSF1 are required for cancer cell proliferation and for the maintenance of genomic stability. Overexpression of DBF4B-FL can protect against DNA damage induced by SRSF1 knockdown and rescues growth defects in SRSF1-depleted cells. Increased DBF4B exon6 inclusion parallels SRSF1 upregulation in clinical colorectal cancer samples. Taken together, our findings identify SRSF1 as a key regulator of DBF4B pre-mRNA splicing dysregulation in colon cancer, with possible clinical implications as candidate prognostic factors in cancer patients.
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•SRSF1 is a key regulator of DBF4B pre-mRNA splicing•DBF4B-FL and SRSF1 are both required for cancer cell proliferation•DBF4B-FL mediates the effects of SRSF1 in tumorigenesis in mice•These findings have potential clinical implications for cancer development
Chen et al. find that SRSF1 is a key regulator of DBF4B pre-mRNA splicing in colon cancer cells and demonstrates that SRSF1 prevents DNA damage and promotes tumorigenesis through its regulation of a DBF4B-FL splice variant.
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